Terminal resiliently secured to an insulating base



Dec. 17, 1963 RENAUD 3,114,818

TERMINAL RESILIENTLY SECURED TO AN INSULATING BASE Filed Jan. 26, 1961 i ll 72 IIIIIIVIIII I F Inventor/s:

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United States Patent 3,114,818 TERMENAL RESILKENTLY SECURED TO AN INSULATING BASE Robert A. Renaud, Corpus Christi, Ten, and Joshua Loring, In, Norton, Mass, assignors to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Filed Jan. 25, 1961, Ser. No. 85,099 16 Claims. (Cl. 260-466) This invention relates to a new and improved terminal construction which provides for firmly securing a terminal to a base or housing member, and also for improved connection between an electrical conductor and a terminal.

It is one object of the invention to provide a novel and improved terminal construction whereby a terminal member can be fixedly and firmly attached to another member, such as a base member, in a simple and economical fiashion.

It is another object of the invention to provide a terminal construction and a method of making the same whereby the terminal can be firmly and securely attached to a base member formed of a frangible or relatively brittle material without incurring cracking or fracture of the base member.

It is a further object of the invention to provide a terminal construction and a method of making the same wherein the terminal is fixedly and firmly secured to a base member and will remain tightly secured thereto during operation at elevated temperatures.

It is a further object of the invention to provide a terminal construction wherein the terminal, after being fixedly and tightly secured to a base member, resiliently maintains its tightness of fit therewith.

It is a further object of the invention to provide a terminal construction which is susceptible to low-cost mass production and is simple and economical to manufacture and assemble.

it is yet another object of the instant invention to provide a terminal construction and a method of making the same, whereby a solid electrical conductor is firmly and securely electrically connected to the terminal member, and yet can flex about the terminal member without creating undue stress in or breakage otthe conductor or of the connection between the electrical conductor and terminal member.

It is another object of the instant invention to provide a novel and improved terminal construction andmethod of making the same, which affords an increased flexing life for a conductor which is electrically connected to the terminal member.

Other objects will be in part apparent and in part pointed out hereinafter.

. The invention accordingly comprises the elements and combinations of elements, steps and sequence of steps, features of construction and manipulation, and arrangements of parts, all of which will be exemplified in the structures and methods hereinafiter described, and the scope of the application of which will be indicated in the following claims.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways.

Also it is to be understood that the phrascology or terminology employed herein is for the purpose of description and not of limitation.

In the accompanying drawings, in which several of various possible embodiments of the invention are illus trated:

FIG. 1 is a top plan view of one embodiment according to the instant invent-ion;

FIG. 2 is a side elevation-a1 view of the construction shown in :FIG. 1, and additionally showing certain parts thereof in a preassembled condition prior to final securement;

FIG. 3 is a view similar to FIG. 2, showing the parts in a final assembled, secured condition;

FIG. 4 is a fragmentary, top plan view showing a modification of a part of the terminal shown in BIG. 1;

FIG. 5 is a fragmentary side elevation (similar to FIG. 2) showing the terminal of FIG. 4 a preassembled condition prior to final securement; and

FIG. 6 is a view similar to FIG. 3, showing the parts of the FIG. 4 embodiment in a final assembled and secured condition.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Dimensions of certain of the parts as shown in the drawings have been modified for the purpose of clarity of illustration.

In the manufacture of electrical components, such as, for example, electrical switches, use is oftentimes made of electrical terminals or electrical contact structures which are mounted on an insulating terminal block, base member, or some other part of a switch structure.

Due to manufacturing tolerances and commercial expediency, it is relatively expensive to have an aperture (into which a terminal is ordinarily inserted) formed in a base member to exactly complement the size and shape of the terminal, so as to eliminate free playaznd looseness of fit between the terminal and the base member. There are many types of electrical switches, for example, of the kind shown in the Bolesky Patent No. 2,199,387, where free play or looseness of fit between the terminal and the base member is objectionable. Such lo'oseness of fit of the terminal may result in deleterious shifts or changes in the calibration of the thermostatic element, particularly where the terminal serves as a statio nairy electrical contact which is engageable with contacts carried by the thermostatic element. It can thus be seen that it is of considerable importance to provide a terminal construction wherein the terminal is mounted to a base member firmly and securely so as to preclude any relative movement therebetween in service or operation.

Conventional staking, resistance welding, or hot rivet upset methods pose many problems and many times are not suitable where the base member is formed of electrically insulating materials that are not resilient or which are frangible and brittle. Such refractory or frangible materials as ceramics glass mica type materials, and various types of refractory materials, have become increas ingly desirable for use in electrical switches because of both their ability to withstand higher elevated temperature conditions than that of phenolic or other resinous organic materials and their characteristic of being relatively chemically inert, which latter attribute is particularly advantageous in obviating contamination and corrosion problems in hermetically sealed, electrical switch applications.

The construction of the instant invention obviates the problems mentioned above, and is applicable to firmly and securely mounting terminals on base members which are formed of either resilient or frangible electrically insulating materials.

Referring now to the drawings, and particularly to FIG. 2, there is shown a base member to which it is frequently desirable to secure one or more terminals for the purpose of electrically communicating between the interior and exterior of a switch housing of which, base member ltl may, for example, form a part. Base 10 may be formed of an electrically insulating material such as often used in electrical switches, which may, for example, include a phenolic or one of the resinous organic thermosetting materials or frangible or brittle materials such as Mycalex (a trademark of the Mycalex Corporation of America for a glass bonded insulated material) or a ceramic material.

Base it) is provided with an open-ended cylindrical aperture 12. As shown in FIGS. 2 and 3, a cylindrically shaped tubular projecting portion 22 forming a part of an electrical terminal, generally referred to by numeral 29, is received and disposed within aperture 12. Cylindrical tubular portion 22 includes an open end 24 and a closed end 26. Advantageously, according to the instant invention, the tolerance of fit between aperture 12 and tubular portion 22 is not critical, and substantially large and inexpensive commercial tolerances may be employed. Terminal member is formed of an electrically conductive material such as, for example, brass, Phosphor bronze or beryllium copper.

Terminal 20 includes an annularly extending, resilient, flared, curved flange portion formed integrally with, and adjacent, the open end of tubular portion 22, as shown. Resilient, flared, curved flange portion 39 may also be characterized as a springy or flexible troughforming portion, the peripheral portion of which is adapted to abut surface 32 of base 10 adjacent aperture 12.

The closed end 26 of tubular portion 22 is adapted to be electrically connected to an electrically conductive member 34, as shown. Electrically conductive member 34 may comprise, for example, an electrical contact, such as those formed of bilayered or trilayered material. An exemplary trilayered contact material is illustrated in FIGS. 2 and 3 and may comprise two layers of silver 36 and steel 38, sandwiching and bonded to a layer of copper 40. The trilayered material 34 need only have a relatively thin cladding of silver with the remainder of the contact and terminal construction formed of relatively inexpensive base metal. The invention thus permits utilization of less expensive contact materials than those required by many prior riveted or welded constructions which generally employ solid silver rivet or weld members, or silver clad base metal rivet members, to provide desired electrical conductivity and desired low resistance electrical connection between parts.

When the parts have been preassembled in the manner described above, and as shown in FIG. 2, electrically conductive member 34 is firmly secured and electrically connected to the tubular portion 22, as at the closed end as, for example, by pressure or resistance welding or by hot upset riveting in the direction shown by the arrows in FIG. 3. During the pressure welding, resistance welding or rivet upsetting step, resilient, flared flange 3% tends to flatten out (from the dashed line to the solid line position shown in FIG. 3) and to move into resilient pressure engagement with surface 32 of base member Mb. The welding operation not only electrically and fixedly secures the electrically conductive member 34 to the tubular portion of the terminal, but also places the electrically conductive member 34 in abutting engagement with surface 42 of base 10 and stresses (flattens) resilient flange 30 into intimate resilient spring-like pressure engagement with opposite surface 32 of base member 10 to firmly mount the terminal on the base member.

Advantageously, because of the resilient flange 3t? pres sure control of the welding or riveting operation is not critical. Spring-like resilient flange 36 tends to deform and assume a flatter configuration upon the application of a force thereto, to thereby distribute the pressures and stresses (created by the welding or riveting operation) over an enlarged area, and substantially eliminate the problems of breakage and cracking heretofore encountered with many prior methods and constructions.

The stresses incurred in cooling and shrinkage of the terminal after welding are also advantageously distributed over a large area of the base by the resilient flange 39 which tends to further flare out or flatten upon the creation of these stresses, to further obviate or at least minimize stress concentrations and potential breaking and cracking of the base.

The cylindrical tubular portion 22 of terminal 20 further has the advantage of tending to collapse internally due to welding forces and pressures created during and after welding (upon cooling) which uniquely serves to reduce the transfer of stresses to the adjacent walls of the holes 12 in the base lfl. By so tending to collapse, the instant terminal construction further assures minimizing the dangers of breakage cracking of the base member.

Tightness of fit between parts is assured by the resilient, spring-like, flared flange which is in pressure engagement with the base It), as above described. When the construction is subjected to elevated temperatures during operation, dimensional changes which may take place due to unequal thermal expansion will not result in looseness of fit, such tendencies for looseness of fit being obviated by the resilient pressure engagement of flange 39 with base 10, as described above. The versatility of the form of the collapsible tubular portion 22 and the ability of the resilient flange to maintain the parts in a tight and firm assembled relation (through the resilient pressure engagement of flange 34 with surface 32 of base it?) perm ts larger tolerances of fit between parts.

While it is preferred that the free closed end 25 of the tubular portion 22 project beyond surface 42 of base member It in the preassembled position shown in FIG. 2, such is not critical. The outer end of closed end 26 may also lie somewhat below surface 42 within aperture 12 (in the preassembled condition as shown in FIG. 2), and still be connected to electrically conductive member 34 and base It) as described above. In this situation, flange 36) would flatten sufficiently to move the outer surface of closed end 26 into engagement with electrically conductive member 34 for electrical connection thereto. It should be understood that either electrically conductive member 34 or closed end portion 26 may be provided with weld projections such as, for example, in the form of a weld ring or a plurality of spaced discrete projections, to facilitate welding and assure proper desired electrical connection between parts.

In FIGS. 4-6 is shown a form of the invention which is like that in FIGS. 1-3, to the extent shown by the corresponding reference numerals in FIGS. 4-6, and to that extent repetition of the description will not be necessary. In this modification, the form of tubular portion 22' (analogous to cylindrical tubular portion 22 in FIG. 1) is modified. Tubular portion 22 is cylindrical and is open ended, as at 24 and St). The open end 5ft of tubular portion 22' is castellated, and provides a plurality of spaced, peripherally arranged weld projections 52, as shown. Weld projections 52 serve to facilitate welding of tubular part 22 to electrically conductive member 34, and to assure desired low resistance electrical contact therewith.

FIG. 5 (analogous to FIG. 2) shows the parts in a preassembled position. FIG. 6 (analogous to FIG. 3) shows the parts in final assembled condition, the parts being secured together in the manner described above for the FIG. 1 form of the invention.

Except for the castellated upper portion of tubular portion 22, the construction of the FIGS. 4-6 form of the invention is like the form shown in FIGS. 13 described above and additionally provides substantially all of the advantages thereof.

Electrical Terminal and Conductor Construction and filer/d Another problem frequently encountered in the art of providing electrical components of the class described above, has been that of breakage of electrical leads or conductors which are electrically connected to such terminal'members. In the past, such electrical leads or conductors have been either welded, brazed or crimped to such terminal members. Considerable flexing and bending of such electrical leads about their point of connection to the terminal members generally takes place in handling, assembly and usage of the devices in which they are incorporated, which has frequently resulted in considerable breakage, at the point of weld or connection of the conductor leads to the terminal, particularly where solid, wire-like conductor leads are employed. This breakage due to flexing of the conductor about the point of weld or connection, is due, at least in part, to the embrittled (and generally reduced) area of the conductor adjacent to the point of weld. Such embrittlement is generally the result of the welding or brazing operation. Such solid conductors in prior constructions generally have had a relatively short flexing life with breakage in many cases being experienced after flexing the conductor only two or three times.

The instant invention uniquely and inexpensively obvivates these problems, and provides a construction which affords a firm and secure electrical connection between parts, and yet provides a connection which affords a relatively long flexing life for the electrical conductor leads. The invention is particularly useful for solid electrical type conductors.

Referring now to FIGS. 2 and 3, terminal includes an elongated flat, electrically conductive member 60 formed integrally with resilient flared flange 30. Elongated member 60 extends transversely to tubular portion 22, as shown, and includes a return bent portion 62 which overlies and is spaced from the elongated member 60. The free end 64 of return bent portion 62 extends in a direction toward tubular portion 22, as shown. The bight portion 66, which interconnects return bent portion 62 and elongated member 60, is provided with an aperture 68, and is also enlarged as shown at 70. Aperture 68 receives a portion or one end of an electrically conductive lead member 72, as shown in FIG. 2. Electrically conductive lead 72 may, for example, comprise a solid copper wire conductor. Portion '73 of electrical conductive lead 72 is disposed intermediate and sandwiched between return bent portion 62 and elongated member 60, as shown. Return bent portion 62 and elongated member 60 are electrically connected as, for example, by squeeze welding, to portion 73 at a point or points W, spaced from aperture 63. This arrangement advantageously permits flexing of the conductor 72 about edges F of aperture 68 (as a fulcrum as shown in the dashed line positions in FIGS. 3 and 6), with the point of flexure or bending remote or isolated from the weld area or points of connection. The flexing portion of conductor 72 adjacent fulcrum F is not stressed, deformed or embrittled by the welding or securing operation at points W. This feature contributes to providing a flexing life which is considerably greater than that of prior constructions wherein the point of flexure is at or close to the points of connection. Portion 70 of return bent portion 62 remains spaced from conductor 72 after welding (as shown in FIG. 3) to facilitate and permit flexure of conductor 72 about fulcrum F. The sandwich-type construction described above also provides for increased strength at the point of weld to afford improved and greater shearing strength.

The terminal-conductor-lead construction described above can economically be produced and assembled. In practice, the elongated member 60 is provided with an aperture and thereafter the free end of member 69 may be bent into the form, as shown in FIG. 2, to provide the return bent portion 62, and bight portion 66 with the aperture 68 therein, as shown. Thereafter, electrically conductive lead 72 is inserted in aperture 68 and the parts secured together, as for example, by squeeze welding. It should be understood that it is also within the purview of the instant invention to clamp weld or to use other convenient means of securing return bent portion 62, portion 73 of conductor 72, and elongated member 60 together for the desired electrical connection therebetween. I

It should also be understood that while a solid, wirelike conductor 72 has been described and illustrated in the drawings, that other forms and shapes of electrical conductors may be employed in the practice of the instant invention. It is intended that the term wire-like include such other forms which may, for example, be rectangular or polygonal in cross section.

It is to be understood that the word terminal as variously employed throughout the specification and claims is intended to include any current conducting, prong, terminals per so, contact structure or combination terminals and contacts.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense, and it is also intended that the appended claims shall cover all such equivalent variations as come within the true spirit and scope of the invention.

We claim:

1. In combination: a base member; said base member being provided with an open-ended aperture; a terminal comprising a tubular member disposed in said aperture and having one end disposed adjacent one surface of said base member, said terminal having a resilient, flared, flange portion adjacent another end of said tubular memher and disposed in abutting engagement with another surface of said base member; another member secured by welding to said one end of said tubular member and abutting said one surface of said base member, said flared flange portion being in resilient pressure engagement with said base and tending to flatten thereagainst when said another member is secured to said tubular member.

2. l n combination: a base member formed of electrically insulating material; said base member being provided with an open-ended aperture; an electrically conductive terminal comprising a tubular member disposed in said aperture and having one end disposed adjacent one surface of said base member, said terminal having a resilient, flared, flange portion adjacent another end of said tubular portion and positioned for abutting engagement with another surface of said base member; an electrically conductive member secured by welding to said one end of said tubular member and abutting said one surface of said base member, said flared flange portion being in resilient pressure engagement with said another surface of said base member and tending to flatten thereagainst when said electrically conductive member is secured to said tubular member.

3. In combination: a base member formed of electrically insulating frangible material; said base member being provided with an open-ended aperture; an electrically conductive terminal having a tubular portion disposed in said aperture, said terminal having a resilient, flared, flange portion adjacent one end of said tubular portion and positioned for abutting engagement with one surface of said base member; the other end of said tubular portion being closed; an electrically conductive member secured to the other end of said tubular portion and abutting another surface of said base member, said flared flange portion being in resilient pressure engagement with said one surface of said base member and tending to flatten thereagainst when said electrically conductive member is secured to said tubular portion.

4. The combination as set forth in claim 2 and wherein said base member is formed of a frangible material, and said other end of said tubular portion is open.

5. in combination: a base member formed of an electrically insulating material; said base member being provided with an open-ended aperture; an electrically conductive terminal member having a cylindrical tubular portion disposed in said aperture, said tubular portion having an open end and a closed end, said terminal having a resilient, flared, curved, annularly extending flange portion adjacent and integral with the open end of said tubular portion and disposed in abutting engagement with one surface of said base member, said closed end of said tubular portion having an electrical contact member welded thereto, said contact member abutting another surface of said base member; said flared, flange portion being in resilient pressure engagement with said one surface of said base and being at least partially flattened thereagainst when said electrical contact member is welded to said closed end of said tubular portion.

6. In combination: a base member formed of an electrically insulating material; said base member being provided with an open-ended aperture; an electrically conductive terminal member having a cylindrical tubular portion disposed in said aperture; said cylindrical portion being open ended; said terminal having a resilient, flared, curved, annularly extending flange portion adjacent one ed of said cylindrical portion and disposed in abutting engagement with one surface of said base member; the other open end of said tubular portion being provided with a plurality of annularly arranged weld projections and having an electrically conductive contact member Welded thereto; said contact member abutting another surface of said base member; said flared, flange portion being in resilient pressure engagement with said one surface of said base and being at least partially flattened thereagainst when said electrical contact member is welded to said other open end of said tubular portion.

7. The combination as set forth in claim 6 and wherein said base member is formed of a frangible electrically insulating material.

8. The combination as set forth in claim and wherein said base member is formed of a ceramic material.

9. In combination: a base member formed of electrically insulating material; said base member being provided with an open-ended aperture; an electrically conductive terminal member having a tubular portion disposed in said aperture, said terminal having a resilient, flared, flange portion adjacent one end of said tubular portion and positioned for abutting engagement with one surface of said base member; an electrically conducting member secured to the other end of said tubular portion and abutting another surface of said base member, said flared flange portion being in resilient pressure engagement with said one surface of said base member and tending to flatten thereagainst when said electrically conducting member is secured to said tubular portion, said flange including an elongated electrically conductive member extending therefrom in a direction transverse to said tubular portion, said elongated member including a return bent portion, the free end of said return bent porti-on extending in a direction toward said tubular portion; the bight portion connecting said return bent portion and elongated member, providing an aperture; an electrically conductive lead member having a portion disposed in said aperture and positioned intermediate said return bent portion and said elongated member; and said lead member being secured to said elongated members and said re turn bent portion at a location spaced from said aperture in said bight portion.

10. The combination as set forth in claim 9 and wherein said electrically conductive lead member comprises an elongated, solid, wire-like member.

11. The combination as set forth in claim 10 and wherein said elongated electrically conductive member extends integrally from said flange and said return bent portion overlies said elongated member.

12. In combination: a base member formed of electrically insulating material; said base member being provided with an open-ended aperture; an electrically conductive terminal comprising a tubular member disposed in said aperture and having one end disposed adjacent one surface of said base member, said terminal having a resilient, flared flange portion adjacent another end of said tubular member and positioned for abutting engagement with another surface of said base member; an electrically conducting member secured by welding to said one end of said tubular member and abutting said one surface of said base member, said flared flange portion being in resilient pressure engagement with said another surface of said base member and tending to flat-ten thereagainst when said electrically conducting member is secured to said tubular member, and said flange including elongated electrically conductive means extending therefrom for electrically connecting and securing another electrically conducting member to said terminal.

13. In combination: a base member formed of electrically insulating frangible material; said base member being provided with an open-ended aperture; an electrically conductive terminal member having a tubular portion disposed in said aperture, said terminal having a resilient, flared, flange portion adjacent one end of said tubular portion and positioned for abutting engagement with one surface of said base member; the other end of said tubular portion being open; an electrically conductive member secured to and covering said open other end of said tubular portion; said electrically conductive member abutting another surface of said base member, said flared flange portion being in resilient pressure engagement with said one surface of said base member and tending to flatten thereagainst when said electrically conductive member is secured to said tubular portion.

14. In combination: a base member formed of an elec trically insulating material; said base member being provided with an open-ended aperture; an electrically conductive terminal member having a cylindrical tubular portion disposed in said aperture; said cylindrical portion being open ended; said terminal having a resilient, flared, curved, annularly extending flange portion adjacent one end of said cylindrical portion and disposed in abutting engagement with one surface of said base member; the other open end of said portion having an electrically conductive member secured thereto, by Welding, closing the open end thereof; said last named electrically conductive member abutting another surface of said base member; said flared, flange portion being in resilient pressure engagement with said one surface of said base and being at least partially flattened thereagains-t when said last named electrically conductive member is secured to said other open end of said tubular portion.

15. In combination a base member having a portion formed of a frangible electrically insulating material; said member portion providing an open-ended aperture, a cupshaped hollow tubular member open at one end and closed at its other end, said cup-shaped member being formed of electrically conductive material and being disposed in said aperture with the closed end thereof disposed adjacent one side of said base member; and a second electrically conductive member secured to the closed end of said cup-shaped member by welding and being disposed closely adjacent said one side of said base member; and said cup-shaped member being securely connected to said base member portion.

9 16. The combination as set forth in claim 15 and wherein said second electrically conductive memlber comprises :an electrical contact.

References Ciexl in the file of this patent UNITED STATES PATENTS 1,706,412 Roberts Mar. 26, 1929 10 Gribbie Aug. 30, 1932 Hubbell Mar. 1, 1949 Peters June 9, 1953 Abramson et a1 July 31, 1956 Nicolaus July 23, 1957 FOREIGN PATENTS Italy May 28, 1954 

1. IN COMBINATION; SAID BASE MEMBER BEING PROVIDED WITH AN OPEN-ENDED APERTURE; A THERMINAL COMPRISING A TUBULAR MEMBER DISPOSED IN SAID APERTURE AND HAVING ONE END DISPOSED ADJACENT ONE SURFACE OF SAID BASE MEMBER, SAID TERMINAL HAVING A RESILIENT, FLARED, FLANGE PORTION ADJACENT ANOTHER END OF SAID TUBULAR MEM- 